Effects of Ultraviolet Radiation on Microorganisms and Animal Cells

Parrish, John A.; Anderson, R. Rox; Urbach, Frederick; Pitts, Donald G.

doi:10.1007/978-1-4684-2475-1_5

Cited by 5 publications

(5 citation statements)

References 75 publications

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“…When all the photon energy is transferred to the atoms and molecules that absorb it, the resulting excited states may lead to protein alteration and enzyme inactivation, which may hamper key biologic systems, e.g. through the splitting of peptide bonds, the alteration of sulfide and disulfide bonds, and photochemical oxidation [ 33 , 34 ]. Cyclobutane pyrimidine dimers, which are formed between two adjacent pyrimidines in the same strand of DNA by the cross-linking of cytosine and thymine, are considered the most important products of UV-induced damage to the DNA; they cause local denaturation of the DNA helix, prevent DNA repair, inhibit DNA replication and protein synthesis, damage RNA, lead to the loss of essential metabolic activities and cause cellular death [ 7 , 8 ].…”

Section: Discussionmentioning

confidence: 99%

Acaricidal efficacy of ultraviolet-C irradiation of Tetranychus urticae adults and eggs using a pulsed krypton fluoride excimer laser

et al. 2021

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Background Pulsed ultraviolet (UV)-C light sources, such as excimer lasers, are used in emerging non-thermal food-decontamination methods and also have high potential for use in a wide range of microbial decontamination applications. The acaricidal effect of an experimental UV-C irradiation device was assessed using female adults and eggs of a model organism, the two-spotted spider mite Tetranychus urticae. Methods UV-C light was generated by a pulsed krypton fluoride excimer laser operating at 248-nm emission wavelength. The pulse energy and pulse repetition rate were 5 mJ and up to 100 Hz, respectively. The distance from the light source to the target was 150 mm; the target surface area was 2.16 cm2. The exposure time for the mites and fresh eggs varied from 1 to 4 min at 5–300 mW, which corresponded to UV doses of 5–80 kJ/m2. Post-irradiation acaricidal effects (mite mortality) were assessed immediately and also measured at 24 h. The effects of UV-C irradiation on the hatchability of eggs were observed daily for up to 12 days post-irradiation. Results The mortality of mites at 5 and 40 kJ/m2 was 26% and 92%, respectively. Mite mortality reached 98% at 80 kJ/m2. The effect of exposure duration on mortality was minimal. The effect of irradiation on egg hatchability was even more significant than that on adult mite mortality, i.e. about 100% egg mortality at an accumulated dose of as little as 5 kJ/m2 for each exposure time. Conclusions A high rate of mite mortality and lethal egg damage were observed after less than 1 min of exposure to 5 mJ UV-C pulsed irradiation at 60 Hz. Pending further developments (such as beam steering, beam shaping and miniaturisation) and feasibility studies (such as testing with mites in real-life situations), the reported results and characteristics of the UV-C generator (modulation of energy output and adaptability to varying spot sizes) open up the use of this technology for a vast field of acaricidal applications that require long-range radiation. Graphical Abstract

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Section: Discussionmentioning

confidence: 99%

Acaricidal efficacy of ultraviolet-C irradiation of Tetranychus urticae adults and eggs using a pulsed krypton fluoride excimer laser

et al. 2021

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“…When all photon energy is transferred to absorbing atoms and molecules, the resulting excited state may lead to proteins alterations and enzyme inactivation hampering key biologic systems, e.g. through the split of peptide, alteration of sul de and disul de bonds and photochemical oxidations [30,31]. In the DNA, pyrimidine dimers and cross-linking between cytosine and thymine are considered the most important UV photoproducts formed between two adjacent pyrimidines in the same strand of DNA, resulting in the production of cyclobutane pyrimidine dimers which cause local denaturation of the DNA helix, prevention of DNA repair, inhibition of DNA replication and protein synthesis, RNA damage, loss of essential metabolic activities, and cellular death [7,8].…”

Section: Discussionmentioning

confidence: 99%

Acaricidal Activity of UV-C irradiation on Tetranychus urticae and eggs using pulsed krypton fluoride excimer laser

Gala¹,

Rebane²,

Ambroise³

et al. 2021

Preprint

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Background While pulsed UV-C light sources such as excimer lasers are used in emerging non-thermal food decontamination method, they also have a high potential for a wide range of other microbial decontamination applications. The acaricidal effect of an experimental UV-C irradiation device was assessed using two-spotted spider mite female adults Tetranychus urticae and eggs as a model. Methods The UV-C light source was generated by a pulsed krypton fluoride (KrF) excimer laser operating at 248 nm emission wavelength. Pulse energy and pulse repetition rate were 5mJ, and up to 100Hz rate, respectively. Distance from light source to target was 150 mm with a target surface of 21.6 cm². The exposure time of the mite and fresh eggs varied from 1 to 4 minutes at a power of 300 mW. The post-irradiation acaricidal effects (mites’ mortality) were assessed immediately and measured 24 h post-irradiation. Effects on the hatchability of irradiated eggs were observed daily post-irradiation for up to 12 days. Results The mortality of mites observed with an energy amount of 5 and 40 mJ/mm² was 26% and 90%, respectively. The mortality at 80 mJ/mm² reached 99%. The effect of exposure duration on mortality was minimal. The effect of irradiation of eggs hatchability was even more important, with about 100% mortality with as little as 5 mJ/mm² for each exposure time. Conclusions A high mite mortality and lethal egg damage was already observed after less than 1 min exposure to UV-C pulsed irradiation. Pending further developments and feasibility studies, the current results and features of the UV-C generator (energy output modulation and applicability to varying spot sizes) open up a large field of germicidal applications requiring long-range radiation.

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“…That UV-A has different photobiological effects than UV-B may be significant in systemic photosensitivity (Table I) DNA repair synthesis, UV-A had either no effect or increased DNA repair synthesis [57]. Although UV-B may be more efficient in causing damage to DNA through direct absorption, UV-A has little effect on DNA without sensitization or activation of a secondary molecule ('chromophore') which forms a DNA cross-linking agent that may inhibit lymphocyte proliferation [7]. In skin as well as in lymphocytes, chromophore action is partly mediated by activated oxygen species which may contribute to damage of cell membranes or DNA [7,58,59].…”

Section: Pathogenesis Of Photosensitivitymentioning

confidence: 99%

“…Although UV-B may be more efficient in causing damage to DNA through direct absorption, UV-A has little effect on DNA without sensitization or activation of a secondary molecule ('chromophore') which forms a DNA cross-linking agent that may inhibit lymphocyte proliferation [7]. In skin as well as in lymphocytes, chromophore action is partly mediated by activated oxygen species which may contribute to damage of cell membranes or DNA [7,58,59]. Splenocytes from SLE murine models appear to be more sensitive to UV-A-induced oxidative stress than normal splenocytes [8,9].…”

Section: Pathogenesis Of Photosensitivitymentioning

confidence: 99%